This relates to a medical device used to aid the introduction of another medical device into the body, and to methods of making and using such an introduction-aiding device. More particularly, this relates to an introducer system useful in the placement of a catheter into the body, and to methods of making and using such a system.
In general, sheaths used to facilitate the insertion of devices, such as catheters, into the body are known. A catheter (or other medical device) can be inserted, with the use of a known sheath, percutaneously into the body, and the sheath can be torn off after insertion of the catheter. Tearable sheaths generally are referred to as peelable sheaths. There are also non-peelable sheaths. Peelable sheaths generally are used to introduce devices which are left in (or at least partially within) the patient after the procedure is completed, and a dialysis catheter is one example of a medical device that is left within the patient after a placement procedure. Non-peelable sheaths generally are used when the introduced device is removed at the end of the procedure.
Known peelable sheaths generally include a hub located at the proximal end of the sheath, and the hub can be manually grasped and pulled apart to permit the longitudinal severance of the hub and the sheath thereby to allow the removal of the sheath and hub from about the catheter extending therethrough and from the body. Such known peelable sheath/hub combinations typically are provided with a dilator, and the whole package generally is referred to as a peelable introducer system or simply an introducer system. Introducer systems with non-peelable sheaths also are known.
Some introducer systems, with the dilator inserted into and through the peelable sheath/hub, are designed to be advanced over a guide wire that is indwelling in a vein, artery, or other body cavity of a medical patient. In general, whether or not used with a guide wire, an introducer system is a medical device for insertion into the body (e.g., into a vein, such as the jugular vein, of a patient). In one possible use, the introducer system is placed into a patient""s vein in order to allow a flexible catheter to be placed later within the same vein through the sheath/hub of the introducer system after the dilator component of the introducer system is removed from the sheath/hub component.
Various types of peelable and non-peelable sheaths and introducer systems are available from Boston Scientific Corporation (Natick, Mass.) and other companies. Boston Scientific Corporation provides certain peelable sheaths and introducer systems in its commercially-available Vaxcel PICC kits.
Some known introducer systems include a valve to provide a seal around the catheter introduced through the sheath.
In general, known valved peelable introducer systems include two basic components: (1) a peel-away sheath/hub, where the hub is fixed to the proximal end of the sheath; and (2) a more rigid dilator that is sized to slide and fit snugly into a lumen extending through the sheath/hub. The hub generally is provided either as two identical separate halves (split along the length of the hub) or as a single unit with scoring or perforations on both sides along its length to allow the sheath hub to be broken into two identical separate halves. The dilator has a proximal hub portion and a longer tubular portion, and a passage typically extends through the dilator such that the dilator can be passed over a guide wire, for example. The tubular portion of the dilator is designed to extend through the sheath and the hub, and the proximal hub of the dilator can lock (e.g., via a luer lock) onto the hub of the sheath. A valve is incorporated into the hub of the sheath, and the dilator passes through this valve when the dilator is inserted into and through the sheath/hub. The valve typically is a thin, disk-like membrane.
In a typical use, a known valved introducer system (with the dilator inserted into the sheath/hub and through the valve) is inserted into a patient""s vein (usually over a guide wire that is already in the vein) up to the sheath""s hub such that most or all of the sheath is within the patient""s vein and most of the dilator also is within the patient""s vein, while the hubs of the sheath and the dilator are outside of the patient""s body. The dilator is then removed from the sheath and from the patient""s body. With the dilator removed, the valve is supposed to close and prevent air from entering the vein, which generally would happen if the passage through the sheath was open, because of negative pressure in the vein. The catheter (or other medical device) is now supposed to be inserted through the hub, valve, and sheath and thus into the patient""s vein.
Known valved introducer systems generally have at least two issues. First, the valve may be too rigid to allow flexible devices, such as flexible catheters, to be inserted therethrough. Many catheters do not have enough column strength or rigidity to be passed through a tight valve. Second, if the valve is sufficiently flexible to allow a flexible catheter to be inserted therethrough, the valve may become malpositioned after the dilator is removed. That is, the valve may not close properly after removal of the dilator, and thus the danger of air entering the body or blood leaving the body is not avoided by use of the valve.
In general, the invention relates to a valved introducer sheath and associated methods of making and using such a sheath. The sheath can include a body portion and a proximal hub portion, with a passageway extending through the entire length of the sheath. The passageway is sized to receive a dilator that generally is more rigid than the body portion of the sheath. The elongated body portion of the sheath can be generally circular in cross-section and can have a first section that has a larger diameter than a second section. The body portion of the sheath could have one or more non-circular cross-sectional shapes. Along and within at least a portion of the passageway of the sheath, an elongated valve extends longitudinally. This elongated valve can be formed of foam or other compliant material that will allow the dilator to pass therethrough and that will form a seal therearound, and that will also close and form a reliable seal after the dilator is removed. The elongated valve of the invention also will allow a device more flexible than the dilator (e.g., a catheter) to be passed therethrough, and it will form a seal around such a device and then close and seal after the device is removed.
The valved introducer sheath of the invention can be xe2x80x9cpeelablexe2x80x9d in that the body portion, hub, and valve can be manually broken apart, split, and peeled from around the device that extends therethrough. Once peeled from around the inserted device and removed from the body of the patient, the two halves of the now-split valved introducer sheath typically are discarded. In an alternative embodiment, the valved introducer sheath of the invention is not designed to be peelable.
The elongated valve provides better performance than existing valves in terms of at least the valved introducer sheath""s ability to prevent reliably the influx of air (and/or the outflow of blood) as the dilator is being removed and after it is removed. The elongated valve of the invention can be opened and closed (by, for example, inserting and removing a dilator or other more flexible device such as a catheter) repeatedly without losing its ability to provide a reliable seal. Also, when the dilator is removed from the valve, and no medical device is present in the valve, the valve material is in an unstressed state.
In one aspect, the invention involves a method of producing a valved sheath. The sheath comprises a proximal hub portion, an elongated body portion extending distally from the proximal hub portion, and a passageway extending through the proximal hub and elongated body portions. A foam material is injected into at least some of the passageway. In the foam material, one or more self-sealing slits are formed. The foam material and the one or more slits serve as a valve in the passageway of the sheath.
Embodiments according to this aspect of the invention can include the following features. The foam material can be injected such that the length of the foam material within the passageway is greater than the width of the foam material at any point within the passageway. The foam material can be a closed cell foam. The foam material can be affixed to at least some of an inner surface of the sheath. The self-sealing slits can be formed such that none of them extends in width to an inner surface of the sheath. The self-sealing slits substantially prevent the flow of gas into the passageway of the sheath. Scorings or lines can extend at least some of the length, and on opposite sides, of the sheath, such that the sheath is separable along the scorings or lines. The proximal hub portion can comprise a pair of wings that extend substantially perpendicular to the elongated body portion of the sheath.
In another aspect, the invention relates to apparatus for facilitating the insertion of a flexible medical device into a body. The apparatus comprises a sheath and a valve. The sheath comprises a proximal hub portion, an elongated body portion which extends distally from the proximal hub portion, and a passageway which extends through the proximal hub and elongated body portions. At least some of the elongated body portion is capable of being placed into the body. The passageway is defined by an inner surface of the sheath. The valve comprises a foam material which fills at least some of the length of the passageway, and one or more self-sealing slits are in the foam material. The length of the foam material within the passageway is greater than the width of the foam material at any point within the passageway. None of the slits extends in width to the inner surface of the sheath, and the slits are capable of allowing the flexible medical device to pass therethrough and sealing around the device.
Embodiments according to this other aspect of the invention can include the following features. The foam material can include a proximal section and a distal section, where the one or more slits in the distal section remain sealed as the flexible medical device is introduced first into the one or more slits in the proximal section. The foam material can define a depression in the proximal section, and the depression can have a conical shape for receiving the flexible medical device. The foam material can be a closed cell foam. The foam material can be affixed to at least some of an inner surface of the sheath. A pair of scorings or lines can extend at least some of the length, and on opposite sides, of the sheath, such that at least the sheath is separable along the lines. The valve, too, can be separable with the sheath and can be split into two halves along one of the self-sealing slits. The elongated body portion can comprise at least a first section and a second section, where a first cross-sectional area of the first section is greater than a second cross-sectional area of the second section. The elongated body portion also can comprise a shoulder disposed within the passageway and between the first and second sections. The proximal hub portion can comprise a pair of wings which extend substantially perpendicular to the elongated body portion of the sheath.
In yet another aspect, the invention involves apparatus for facilitating the insertion of a flexible medical device into a body. The apparatus comprises a sheath and a valve. The sheath comprises a proximal hub portion, an elongated body portion which extends distally from the proximal hub portion. At least some of the elongated body portion is capable of being placed into the body. The passageway is defined by an inner surface of the sheath. The valve comprises a foam material which fills at least some of the length of the passageway, and one or more self-sealing slits are in the foam material. The length of the foam material within the passageway is greater than the width of the foam material at any point within the passageway. The foam material is affixed to a portion of the inner surface of the sheath, and the slits are capable of allowing the flexible medical device to pass therethrough and sealing around the device.
Embodiments according to this aspect of the invention can include the following features. The foam material can include a proximal section and a distal section, where the one or more slits in the distal section remain sealed as the flexible medical device is introduced first into the one or more slits in the proximal section. The foam material can define a depression in the proximal section, and the depression can have a conical shape for receiving the flexible medical device. The foam material can be a closed cell foam. A pair of scorings or lines can extend at least some of the length, and on opposite sides, of the sheath, such that at least the sheath is separable along the lines. The valve, too, can be separable with the sheath and can be split into two halves along one of the self-sealing slits. Each of the halves of the valve remain affixed to the respective halves of the sheath when the sheath and valve are separated. None of the one or more self-sealing slits in the foam material extend in width to the inner surface of the sheath. The proximal hub portion can comprise a pair of wings which extend substantially perpendicular to the elongated body portion of the sheath.
In still another aspect, the invention relates to apparatus for facilitating the insertion of a flexible medical device into a body. The apparatus comprises a sheath and a valve. The sheath comprises a proximal hub portion, an elongated body portion which extends distally from the proximal hub portion, and a passageway extending through the proximal hub and elongated body portions. The valve comprises an injected foam material which fills at least some of the length of the passageway, and one or more self-sealing slits are in the foam material. The length of the foam material within the passageway is greater than the width of the foam material at any point within the passageway.
Embodiments according to this aspect of the invention include the following features. The foam material can include a proximal section and a distal section, where the one or more slits in the distal section remain sealed as the flexible medical device is introduced first into the one or more slits in the proximal section. The foam material can define a depression in the proximal section, and the depression can have a conical shape for receiving the flexible medical device. The foam material can be a closed cell foam. In one embodiment, none of the one or more self-sealing slits extends in width to an inner surface of the sheath that defines the passageway. The one or more self-sealing slits substantially prevent the flow of gas into the passageway of the sheath. A pair of scorings or lines can extend at least some of the length, and on opposite sides, of the sheath, such that at least the sheath is separable along the lines. The valve, too, can be separable with the sheath. The proximal hub portion can comprise a pair of wings which extend substantially perpendicular to the elongated body portion of the sheath.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.